Expanded Shale Lightweight Fill: Geotechnical Properties

Abstract

Recently, expanded shale aggregates of the kind used to produce lightweight concrete have been used as a substitute for ordinary fill materials in geotechnical applications where the combination of low unit weight and substantial shear strength is important. The results of triaxial compression tests on large-diameter (25 cm) specimens from several different locations in the eastern United States are presented. Depending on the degree of compaction, the angle of internal friction was found to vary from about 40° to 48° in aggregates that weigh about half as much as most naturally occurring fills. Stress-strain curves for the triaxial tests and for some preliminary consolidation tests are included in the paper so that they may be compared with data for ordinary fills when the lightweight aggregate is being considered as a design alternative.